cos4x = cos2x
We know that:
cos2x = 1-2cos^2 x
==> cos4x = 1-2cos^2 (2x)
Now substitute:
==> 1-2cos^2 (2x) = cos2x
==> 2cos^2 (2x) + cos2x - 1 = 0
Now factor:
==> (2cos2x -1)(cos2x + 1) = 0
==> 2cos2x -1 = 0 ==> cos2x =1/2 ==> 2x= pi/3
==> x1= pi/6 , 7pi/6
==> x1= pi/6 + 2npi
==> x2= 7pi/6 + 2npi
==> cos2x = -1 ==> 2x= pi ==> x3 = pi/2 + 2npi.
<span>==> x= { pi/6+2npi, 7pi/6+2npi, pi/2+2npi}</span>
Our three numbers are...
3 3/10 = 3.3
3.1
3 1/4 = 3.25
So, if we order those from least to greatest, we have...
3.1, 3.25, 3.3
which, in the forms given, is...
3.1, 3-1/4, 3-3/10
Answer:
1:1.2
Step-by-step explanation:
please give me a brainliest!!<3
Answer: 362,880
Step-by-step explanation: At first glance of the question, it doesn't seem that the order matters, which would make it a question of how many combinations there are. The simple way to look at it is that there are 9 trees and he's planting 8, leaving out 1. Since there are 9 possible trees to leave out, there are 9 possible combinations of which 8 trees to plant.
The formula would be 9!/([9-8]!*8!) = 9
If the question is indeed asking for permutations (order matters), since you are choosing 8 out of 9 the formula would be 9!/(9-8)! = 9!/1! = 9! = 362,880
